This invention relates generally to pump drive systems, and more particularly to a novel and improved dual drive pump system in which a single pump may be selectively operated from a power source or may be manually operated.
The present invention is embodied in a dual drive pump particularly suited for charging accumulators used to supply power for starting aircraft engines or the like. As described in my copending U.S. patent application, Ser. No. 243,491, filed Mar. 13, 1981 (assigned to the assignee of the present invention), aircraft are often provided with accumulators which are pressurized to provide the power to start the aircraft engines. Such accumulators are normally pressurized prior to shutting the engine down so that they are charged and available for restarting the engine at a later time.
If for some reason the accumulator loses its pressurized charge, means must be provided to repressurize the accumulator before an engine start can be accomplished. The loss of charge can be caused for any number of reasons, for example, due to maintenance or attempted but unsuccessful engine starts.
In the event that the aircraft is at a remote location where suitable ground equipment is not available for repressurizing the accumulator, it is necessary to provide some means for on-site recharging of the accumulator. At many remote locations, where standard ground support equipment is not available, pneumatic or other types of power tools, such as rotary pneumatic tools or electric tools, are often available which can supply enough power to operate the pump and thereby eliminate the need for manual recharging. In other instances where no such power tools or the like are available to power the pump, it is necessary to provide a system in which the pump can be manually operated. It is therefore desirable to provide a dual drive pump system which can be operated by rotary power tools or the like that are often available even at remote sites or, as an alternative, a pump which can be operated manually so as to recharge such engine starting accumulator.